Bummer. It doesn't look like that feature is maskable in ESX 5.1.
If you can survive without AVX, you could try the following:
featMask.mockup.cpuid.NUMLEVELS = Val:0xb
featMask.mockup.cpuid.AVX = Val:0
featMask.mockup.cpuid.XSAVE = Val:0
Bummer. It doesn't look like that feature is maskable in ESX 5.1.
If you can survive without AVX, you could try the following:
featMask.mockup.cpuid.NUMLEVELS = Val:0xb
featMask.mockup.cpuid.AVX = Val:0
featMask.mockup.cpuid.XSAVE = Val:0